The present invention relates to an apparatus and method for stenting a blood vessel. More particularly, the invention relates to a balloon catheter which may be used to deploy one or more stents in a bifurcation of the blood vessel in order to treat an occlusion or lesion occurring in or near the bifurcation.
Balloon catheters are commonly used to treat certain conditions of a blood vessel, such as a partial or total occlusion or lesion of the vessel which may be caused by, for example, atherosclerotic plagues or thrombosis. In an angioplasty procedure, the balloon portion of the catheter is advanced over a guide wire to the site of the occlusion and inflated to compress the occlusion and thereby restore normal blood flow through the vessel. In some instances, a stent may be implanted in the blood vessel to prevent the occlusion from recurring. A balloon catheter is commonly used to deliver and deploy the stent in such a stenting or stent implantation procedure. The stent is typically mounted in its unexpanded state on the balloon portion of the catheter, delivered to the site of the occlusion and then deployed or implanted in the vessel by inflating the balloon portion.
Prior art stenting procedures often are unsuitable for treating a condition of a blood vessel occurring at or near a bifurcation of the blood vessel, that is, the intersection of a main vessel with a side branch vessel. One method for stenting an occlusion in a bifurcation involves implanting a first stent in the main vessel adjacent the bifurcation and then implanting a second stent in the side branch vessel adjacent the bifurcation (the so-called “T-stenting” procedure). However, this requires that the guide wire for the balloon catheter which is used to deliver the second stent be threaded through the struts of the first stent and into the side branch vessel. This process can be quite difficult and time consuming. Furthermore, the stenting of the main vessel may shift plagues and thereby close off the side branch vessel, making it extremely difficult to insert the guide wire into the side branch vessel.
Also, prior to stenting, the occlusion is commonly pre-dilated using a balloon angioplasty procedure. In preparation for a balloon angioplasty procedure in a bifurcation, a first guide wire is inserted into the main vessel and a second guide wire is inserted into the side branch vessel. Thus, even if shifting plagues should close off the side branch vessel during dilation of the main vessel, the side branch vessel can still be approached via the second guide wire. However, in prior art stenting procedures for occlusions in bifurcations, the second guide wire must usually be withdrawn from the side branch vessel prior to stenting the main vessel so that it will not interfere with the deployment of the stent in the main vessel. Consequently, difficulty may be experienced in inserting the second guide wire back into the side branch vessel prior to stenting or otherwise re-treating the side branch vessel.